1. Field of the Invention
This invention relates to glycol dehydrators and more particularly to a method and apparatus which eliminates noxious gasses normally exhausted to the atmosphere from the still column of a gas dehydrator.
Natural gas produced from gas wells contains entrained water and oil droplets, water vapor, and condensable hydrocarbons.
It is necessary to remove the water and water vapor from the natural gas before it passes into a pipeline to prevent clogging and corrosion of the pipeline and downstream equipment.
Glycol dehydrators are used to remove water and water vapor from gas by contacting the wet gas with glycol absorbing the water and vapor. The desiccant then flows to a reboiler regenerating the glycol by driving off the water vapor, allowing the reconcentrated desiccant to be returned to the dehydration phase.
An unintentional by-product of the dehydration process is the absorption of hydrocarbons with water and water vapor. These hydrocarbons are normally released to the atmosphere with water vapor from the regenerator. Many of these aromatic hydrocarbons are hazardous to the environment, benzene, ethylbenzene, toluene, and xylene for example.
2. Description of the Prior Art
Some prior patents, such as U.S. Pat. No. 3,875,019 issued Apr. 1, 1975 to Cocuzza et al, and U.S. Pat. No. 5,163,981 issued Nov. 17, 1992 to Choi, disclose removing noxious gasses from the vapors emitted by a still column from a reboiler and passing these noxious gasses to the burner of the reboiler. However, a problem occurs in admitting the gasses to the reboiler burner and obtaining combustion since these noxious gasses do not readily burn, as does natural gas. This invention overcomes this problem.
The majority of the prior art patents are directed toward the reclaiming and/or reconcentrating ethylene glycol.
U.S. Pat. No. 4,273,620 issued Jun. 16, 1981 to Knobel, U.S. Pat. No. 4,225,394 issued Sep. 30, 1980 to Cox et al, and U.S. Pat. No. 4,322,265 issued Mar. 30, 1982 to Wood, are considered good examples of the further state-of-the-art in reclaiming and reconcentrating used ethylene glycol.